Purge device for refrigerating systems



J. G. BERGDOLL I PURGE DEVICE FOR REFRIGERATING SYSTEMS Filed Oct. 19; 1925 "2 sheets-sheet 1 Jan. 4 a

i i/X//////////// A Tosucl'ion 1,612,963 Jan. 4,1927. G; BERGDOLL PURGE DEVICE FOR REFRIGERATING SYSTEMS Filed Oct. 19. 1925 2 sheets-sheet 2 s -4 ig 9" N w J z Patented Jan. 4, 1927.

UNITED STATES PATENT OFFICE.

Jean (2. ssnenonn,

OF YORK, PENNSYLVANIA, ASSIGNOR TO YORK MANUFACTUR- ING COMPANY, OF YORK, PENNSYLVANIA, A CORPORATION 01' PENNSYLVANIA.

PURGE DEVICE FOR REFRIGEBATING SYSTEMS.

This invention relates to refrigeration and particularly to the means for purging a system to remove so-called foreign gases.

The foreign gases are chiefly air and some 6' products of the decomposition of lubricating oils,'and being non-condensible at the temperatures and pressures used in the refrigerating system, they have a harmful effect on its operation.

1 condensibility has heretofore been used in purging operations, advantage being taken of selective liquefaction of a mixture of gaseous refrigei ant and foreign gases to separate practically all the refrigerant from the mixture in liquid form. Two characteristically different modes of effecting the final separation after such liquefaction have been followed. In one, the liquid refrigerant is drained away and the remaining gases are 2 completely isolated from the system before venting. In the other, no such isolation is attempted. Instead, an effort is made to chill the non-condensible gases and refrigerant to such an ezitent that the partial pressure of the refrigerant is reduced to a minimum. Consequently, the vented gases consist primarily of foreign non-condensible gases with only such an admixture of gaseous refrigerant as is unavoidable according 5:0 to the law of partial pressures. Under these conditions purging'may take place without isolating-the apparatus from the system.

The last-named mode is advantageous from an operative standpoint because continuous, but it has heretofore been considered objectionable because in prior systems of the continuous type the venting is controlled by pressure and occurs continuously, regardless of temperature. The result is 40 that venting may continue even while the temperature in the purge chamber is high enough to cause serious waste of refrigerant. Aside from this waste, the release of refrig' crant leads to objectionable conditions in. the

4:) plant.

The present invention secures all theadvantages of continuous operation without the disadvantages attendant u on prior'systems, and the result is secured hycontrolling h" the dischar e, not by pressure, but by'temperature. he simplest modeknown to me of availing of this principle is to discharge through a thermostatically controlled valve which is subject to the temperature at the This characteristic of non-.

below a safe value characteristic of the adj ustment of'the thermostat, the thermostatically controlled vent valve opens slightly, permitting the necessary venting. In higher temperatures the vent valve closes. It is not ordinarily desirable to chill the whole quantity of liquid refrigerant, and to avoid this I make use of a purge drum so connected to the system that it draws from the liquid line or from the receiver only a mixture of foreign gases and uncondensed refrigerant. Thus the quantity of 11 uid refrigerant which must be sub-coole is reduced to a minimum.

The most'eifective way of collecting this gaseous mixture is to place a trap in the liquid line between the condenser and the receiver and connect the purge drum to the top of the trap. Another effective way is to use the receiver itself as a trap and connect the top of the receiver to the purge drum. Other arrangements are possible, but the two mentioned are preferred in the order stated and each is described as embodied in one practical installation. These embodi- Fig. 3 is an elevation, partly sectional,

of a modification in which the purge drum has a gas connection to the top and a liquid connection to the bottom of the receiver.

' An ordinary atmospheric type of condenser is diagrammatically illustrated at 6 and its liquid and stop valve 10 to the usual receiver 11. The trap 9 is designed to permit the passage of i uid and to arrest the passage of gas, and rom the top of the trap 9 there header at 7. From the header 7 the liquid line 8-.1eads through a trap 9' leads a connection 12 to the interior of a purge drum'13. The connection .12 is con trol ed by a stop valve 14.

' The form. of the purge drum 13 is clearly shown in the drawings and is subject to considerable variation. It is provided with a cooling element which, in the example illustrated, takes the form of a central shell or drum 15 servin as an expansion cooler. The left end is %ed with liquid refrigerant through an expansion valve 16 WhlCh is supplied by a pipe 17 leading from the receiver 11 or from any other available source bottom of the purge drum 13 and from time to time this is drawn off through the expansion valve 21 and allowed to expand into the shell 15 to produce the desired refrigeration. At such times the expansion valve 16 is closed. This operation serves the double purpo:e of draining the purge drum 13 of liquid refrigerant and of a plying usefully the refrigerant so salvaged? Leading from the top of the purge drum 13 is a pipe connection 22 which carries a pressure gauge 23. A gauge glass 24 is interposed between the connections 20 and 22 and serves to show the liquid level in the purge drum 13. This gauge glass is equipped with the usual stop cocks 25. Also leading from the connection 22 is the purge or vent pipe 26 which is controlled by a manually operable. stop valve 27 and also by a thermostatically actuated stop valve, indieated generally in Fig. 1 by the numeral 28 applied to the valve body. The construction of this valve is shown in Fig. 2.

The valve body 28 is formed with a ported reat 29 with which coacts a needle valve 30. Theneedle valve 30 is longitudinally slidable in a sleeve 31 which is screwed into the valve body 28 and locked therein by a nut 32. Formed on the upper end of the sleeve 31 is the lower half 33 of a diaphragm housing whose upper half 34 is connected thereto by bolts 35. The diaphragm 36 is clamped between the two halves 33 and 34 and actuates the valve 30 through a convex head 37 which bears against the diaphragm 36 and which is in thrust relation with the valve 30.

The convex head 37 is guided in part by the projections 38 which extend through openings in the lower half 33 of the diav The space above the diaphragm 36 is in communication through a pipe 43 with a thermostatic tube 44 closed at its end and mounted within the purge chamber 13. Any suitable volatile liquid might be used as the expanding agent, but I prefer to use as the expanding agent some of the refrigerant used in the system for the reason that the thermal characteristics of the vent valve can be made identical with the thermal characteristics of the refrigerant in the system. 7 For this reason I provide a branch pipe 45 leading from the liquid branch 17 through a stop valve I 46 to the junction of the pipe 43 and tube 44. By this means the thermostatic element is charged with liquid refrigerant, after which the valve 46 is closed and remains closed during the: operation of the device. The valve 47 serves as a means for discharging the thermostatic-liquid upon occasion.

A mercury well 48 and thermometer 49 afl'ord means for ascertaining the temperature in the purge drum.

Assuming the system so constructed, the firststep for putting the purge apparatus into action is to charge the. thermostatic tube 44 and pipe 43. Starting with all valves closed, the valve 16 is first opened, causing liquid refrigerant to expand into the shell 15 and chill the dru'm.- Then the temperature in the drum reaches 30. the valve 46 is opened wide and then clo'ed tightly. The valve 47 is then opened for a few seconds 'to vent air from the pipe 43 and tube 44. and then closed tightly.

The next step is to adjust the valve spring 40. The valve 14 is opened and the tempcrature in the purge drum 13 rises.

The

nut 41 on the thermostatic valve should be in its lowest position. The valve 27 l.) then opened slightly, say one-third of a turn. As the foreign gases accumulate in the purge drum 13. the temperature will gradually fall. When it reaches the proper value. usually about 20 F., the spring-adjustiug nut 41 on the thermostatic vent valve is turned up slowly until the vent valve opens. The valve 27 is then adjufited togive thev slowest venting rate ponsistent with proper purging, an adjustment which mustbe determined by trial.

The action of the device may be very briefly outlined. The trap 9 arrests the mixture of foreign gases and uncondensed redrum 13 will be approximately the pressure on the liquid line and so long as the tempera,- ture remains below the thermostat settlng, the valve 30 Wlll remain open and purging will continue at a rate determined by the adjustment of the valve 27'. a If the temperature in the purge drum '13 rises above the thermostat setting for any reason, the resulting riseof pressure in the tube 44 and pipe 43 will, through the action of .the diaphragm 36, close the valve 30' against the opposition of the spring 40. Thus purging is subject to the temperature in the purge drum 13 and not to the press sure therein. Hence it will cease automatically if the refrigerating action of the central shell should cease for any cause.

The condensation of gaseous refrlgerant entering the purge drum 13 through the pipe 12 is an incident to the operation of. the device. This accumulation is indicated by the.

gauge glass 24, and when the purge drum 13 is approximately one-third full it is advisable to close the expansion valve 16 and open the expansion valve 21 until this accumulated liquid refrigerant shall have been drawn off. After this, and the valve 16 is opened.

To indicate the general applicability ofv the invention, the modification shown in Fig. 3 will now be described.

51 represents diagrammatically a vertical shell and tube condenser, and52 is the liquid line leading through a stop valve 53 to the receiver 54. The purge drumi's shown at v55 and has from its bottom a liquid return connection 56 controlled by a stop valve 57 and leading to the bottom of the receiver 54 through the connection 58. From the top of the receiver 54 is a gas connection 59 which leads through a stop valve 60 to a point near the lower end of the side of the purge drum 55. 7 Valve 57 is normally open.

The purge drum 55 is provided with a ress'ure gauge 61 and athermometer 62,-and 1s chilled by the action of an expansion coil 63 which is fed from the branch 64 of the liquid line through an expansion valve 65.

The coil 63 is connected to the suction line through a valve 66. The purge or vent pipe 67 is controlled by a sto valve 68. and a thermostatically controlle valve 69 identical in construction with that shown in Fig. 2;

' The thermostatic tube is functionally-iden- 44 already described, and

tical with the tube This tube is connected is shown at 70.

through a p pe diaphragm of the thermostatically con- 1 trolled valve, exactly as heretofore described.

The tube 70 and the pipe 71 are charged with refrigerant from the branch liquid line-64 1 the valve 21 is closed system 71*with the space above the from the bottom of the receiver 54 and hence the liquid refrigerant in the receiver produces a trap seal. Accordin ly, foreign gases and gaseous refrigerant owing from the condenser 51 are trapped in the upper portion of the receiver 54 and pass through the pipe 5910 the purge drum 55. It will be understood that the expansion valve 65' isopen, that the valve 66 is also open and that thecooling coil 63 is still in constant action. 'It follows that there will be selective condensation of refrigerant in the drum 55. This acts to draw gases from the top of the receiver and to'deliver liquid refrigerant only back to the bottom of the receiver, 'so that the foreign gases tend to; accumulate in'the mrge drum 55. So long|as the cooring coil '63 maintains the temperature in tn1s drum at the desired low point, the valve 69 remains open and purging continues at a rate determined by the adjustment ofthe valve 68. This rate is made as slow as is consistent with effective purging.

carry a part of the cooling load on thepurge drum, in the other it is automatically returned to the receiver.- Both have the characteristic of controllin the purging by the temperature within th purge drum and not by pressure, and both have the advantage that purging can occur only while the temperature at the point of purging is below a chosen value ensuring a minimum loss of refrigerant. f

This control according to temperature effected by the use of the thermostatically controlled valve is one of the important features of the invention and'obviously it may be availed of in embodiments differing from the two specific ones above illustrated. These embodiments are chosen for purposes of explanation and do not imply any necessary limitation to those particular embodiments.

What is claimed is:

,1. The con'ibination with a refrigerating of a purge valve adapted to vent from the refrigerating system at a at which the refri erant is normally thermostat c actuagases point in a liquid state; and a tor operatively connected with said valve, subject to the temperature in the system adj'acent the valve and valve only at temperatures low enough to arranged to open the &

preclude discharge of refrigerant in substantial quantity.

2. The combination with a refrigerating system of a purge valve adapted to vent gases from the refrigerating system at a point at which the refrigerant is normally in a'liquid state; a thermostatic actuator operatively connected with said valve, subject tothe temperature in the system adjacent the valve and arranged to. open said valve only at a temperature lower than the normal temperature of such liquid refrigerant;

and means for producing a localized cooling sufficient to cause said valve to remain open for substantial time periods.

3. The combination with a refrigerating system of a purge valve adapted to vent gases from the refrigerating system; a thermostatic actuator operatively connected with said valve; subject to the temperature of gases flowing thereto and arranged to open said valve only at temperatures below the normal temperature of gaseous-refrigerant in the system adjacent the point of purging; and means for chilling below such. normal temperature gases adjacent said valve.

4. The combination with a refrigerating system of a purge valve adapted ,to vent gases from the refrigerating system;'and a thermostatic actuator for, said valve comprising a confined volume of the volatile fluid used as a refrigerant 1n the system,

- upon-,rise of temperature.

flow ng to saidvalve.

subject to the temperature of ases flowing to'the valve and arranged to clbse the valve 5.The combination with' a refrigerating system of a purge valve adapted to' vent gases from the refrigerating system; a thermostaticactuator for said. valve comprising y a-confined volume of the volatile fluid used as a refrigerant in the system, subjecttothe temperature of gases flowing to the valve and arranged to close' the valve upon rise of ling gases temperature; and means for chi 6. The combination with a refrigerating system of a purge drum in communlcation therewith; means for chilling said drum;

and event valve having a thermostatic control element subject to the temperaturewithin said drum said valve being arranged to open and ventuncondensed gases from said drum below a given temperature and vto close athigher temperatures.

7. The combination with a refrigerating svstem of a purge drum in communication .therewith;'means for chilling said drum, operable at least in part by liquid refrigerant condensed in said drum; and a vent valve having a thermostatic control ele fluent subject to the temperature within said drum, said valve being arranged to open and vent uncondensed gases from the drum be- .low a given temperature and to close above such temperature.

- one to the other.

8. The combination with a refrigerating system having a liquid conducting line, of a gas-arresting trap interposed in said line; a purge valve connected with said line in 9. The combination with a refrigerating system containing a volatile refrigerant, of a valve arranged to discharge gases from said system; and thermostatic controlling means for the valve subject to the temperature of gas in the system and arranged to close the valve upon a rise of temperature.

10. The combination with a refrigerating system of a purge valve connected to discharge gases only and having a thermostatic control element, arranged to open the valve only at low temperatures adjacent the inlet Q to the valve; and means for exerting a local refrigerating action sufficient to liquefy substantially all gaseous refrigerant adjacent such inlet to the purge valve.

. 11. The combination with a refrigerating system containing a volatile refrigerant,

of a valve arranged to discharge gases from said system; thermostatic controlling.

means for the valve subject-to the temperatureof gas in the system and arranged to close the valve upon a rise of temperature; and adjusting means operable ,to vary the temperature at which the thermostatic controlling means closes the valve.

12. The combination with a refrigerating system having a portion normally containmg liquid refrigerant and gaseous or vaporous refrigerant,,and at times containing also foreign gases, ofa purge chamber; a

connection from said portion to the purge chamber arranged to prevent entrance of liquid refrigerant into said chamber while permitting the free entrance of all gases or vapor; means for withdrawing liquefied refrlgerant from said chamber; means for cooling said chamber below the normal temperatureof the refrigerant adjacent said connection; a purge valve leading from said chamber; and a thermostatic control device subject to the temperature in said; chamber and connected with said valve to close the same when the temperature in said drum exceeds a chosen valve lower than said normal. temperature.

In testimony whereof Ihave signed my I name to this specification.

JOHN G. BERG-DOLL.-

Certificate '0: Correction. V It is hereby certified that in Letters Patent No. 1,612,963, granted anuary 4,

'1927, upon the ap lication of John G. Bergdoll, of York, Pennsylvania, for an improvement in urge Devices for Refrigeratin Systems, an error appears in the printed specification requiring correction as fol ows: Page 4, line 125, claim 12, for theword valve read value; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflioe. g I a Signed and sealed this 1st day of February, A. D. 1927.

M. J. MOORE, ATdting Gammdssimmr of Patents. 

